1. Field of the Invention
The present invention relates to a heat exchanger, in particular a heat exchanger of a motor vehicle, comprising cooling tubes and comprising collecting tanks, in which the cooling tubes extend between the collecting tanks, in which the cooling tubes and the collecting tanks can be spatially connected to each other, in which the cooling tubes can be produced from a strip material having at least one cooling tube seam, in which the cooling tube seam can form an inner partition wall of the cooling tube, and in which the cooling tubes can have an outer brazing layer on the outside of the tube. The invention furthermore relates to a method for producing a cooling tube of a heat exchanger, in which a strip material is provided with at least one seam, and in which the strip material is bent and joined to form a cooling tube having at least one seam.
2. Description of the Background Art
Heat exchangers having cooling tubes and collecting tanks are known from the conventional art and are used predominantly in the automotive industry.
Cooling tubes mounted, in particular, on motor vehicle heat exchangers, also frequently referred to as seamed tubes, are often designed as longitudinally seam-welded flat tubes into which suitable longitudinal seams or beads are embossed, with the aid of which partition walls may be implemented to form separated chambers inside the flat tubes.
A first heat exchanger of this type is known, for example, from DE 698 21 385 T2 of the European patent application EP 1 030 155 B1, which both correspond to U.S. Pat. No. 6,799,630, and in which a tube is produced from a brazing sheet which is brazed on both sides. For this purpose, beads are embossed in the brazing sheet, and the brazing sheet is folded in such a way that two brazing sheet members are located directly opposite each other, thereby forming the actual flat tube. The beads form partition walls inside the flat tube, a bead of a first brazing sheet member adjoining the opposite brazing sheet member. During a suitable brazing process, in which the brazing material is melted onto the brazing sheet, the adjacent areas of the brazing sheet are joined together. Due to an unfavorable and/or insufficient brazing process, however, there is the danger that a bead is not sufficiently brazed to the adjacent brazing sheet member in the inside, which, with respect to the partition walls, enables leaks and/or overall pressure resistance problems may arise in the heat exchanger.
To counteract this problem, a heat exchanger having flat tubes as cooling tubes is furthermore known from the unexamined patent application DE 195 10 283 A1, in which the flat tubes have inwardly embossed seams which may also form partition walls within the flat tubes. To join two such opposite seals together in a particularly dependable manner, in particular in a liquid-tight or gas-tight manner, in the form of partition walls within the flat tubes, the opposite seals are joined together in their raised regions using an inductive hot pressure welding method.
In the aforementioned examples, the flat tubes also have a brazing layer on their particular outsides in order to be easily structurally brazed to other components of the heat exchanger, for example corrugated fins. Brazing the heat exchanger components may preferably be carried out using a common brazing process in a shielding gas continuous furnace, for example using fluxing agents.